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Surge impedance of a┬а transformer is in the range of
80 to 100 ╬й
400 to 500 ╬й
1000 to 2000 ╬й
None of above
1000 to 2000 ╬й
The surge impedance of a transformer is a measure of its characteristic impedance for traveling waves, typically ranging from 1000 ╬й to 2000 ╬й. It is significantly higher than that of overhead transmission lines, which usually range from 400 ╬й to 500 ╬й, due to the high series inductance of the transformer windings.
The surge impedance of a transformer is a measure of its characteristic impedance for traveling waves, typically ranging from 1000 ╬й to 2000 ╬й. It is significantly higher than that of overhead transmission lines, which usually range from 400 ╬й to 500 ╬й, due to the high series inductance of the transformer windings.
ZsтАЛ=CLтАЛтАЛ тАФ Surge impedance defined by series inductance and shunt capacitance
The surge impedance (ZsтАЛ) is defined as the square root of the ratio of the series inductance (L) to the shunt capacitance (C) of the component. For a transformer, the high number of turns results in a large equivalent series inductance, which dominates the expression and elevates the value of ZsтАЛ compared to cables or lines. When a high-frequency voltage surge enters a transformer, the winding acts as a complex network of inductance and capacitance, with ZsтАЛ=CLтАЛтАЛ.
Surge impedance represents the ratio of voltage to current for a traveling wave.
Transformers have high surge impedance due to high winding inductance.
The range of 1000 to 2000 ╬й is specific to standard power transformers.
Surge impedance is critical in analyzing the behavior of lightning and switching surges.
Helps in designing proper insulation coordination.
Assists in selecting appropriate surge arresters to protect equipment.
Higher surge impedance leads to larger voltage magnitudes during transient events.
Increases the likelihood of dielectric stress within the transformer windings.
Power system insulation coordination studies.
Analysis of transient overvoltages during switching.
Coordination of lightning protection systems.
Overhead transmission lines typically have a surge impedance in the range of 400 ╬й to 500 ╬й.
Underground cables have a much lower surge impedance, typically 30 ╬й to 50 ╬й.
Option A (80-100 ╬й) is closer to the value of some specialized cables or lines, not transformers.
C is correct тАФ The surge impedance of a transformer typically lies between 1000 ╬й and 2000 ╬й due to its high series inductance.
Always remember that surge impedance decreases as the shunt capacitance increases (e.g., in cables), whereas components with high inductance (e.g., transformers) possess significantly higher surge impedance.